1. Field of the Invention
This invention relates to a seal device for waterproof sealing between a surface and an elongate member projecting through that surface. The device is particularly suitable for sealing about vent pipes, and other pipes and conduits, projecting through an outer surface of a tiled or metal deck clad roof, and it will be convenient to hereinafter describe the invention in relation to that exemplary application. It is to be appreciated, however, that the seal device is not limited to that application.
2. The Prior Art
Traditionally, metal flashing has been used to waterproof seal between a roof covering and an elongate member projecting therethrough, although in recent years seal devices have been specifically developed as a substitute. Examples of such seal devices are disclosed in Australia patents 514247 and 568737, as well as Australian design registrations 82275, 90304, 90305, 91270, 91271, 91272, 91723, 97582 and 97740.
Whilst these devices function generally satisfactorily, they are often subject to unacceptably high manufacturing rejection rates, and are generally expensive to manufacture. That is particularly so where, during manufacture, a flexible non-metallic part of the device is molded to a deformable, non-resilient metallic part. The molding apparatus, and in particular the molding die, is required to be of sufficient size to accommodate the metallic part, and sometimes that metallic part is quite large even though the non-metallic part to be molded is relatively small. As such, large and expensive molding apparatus may have to be allocated to relatively small molding tasks in manufacturing the seal device.
In addition, the use of readily deformable metallic parts, such as those composed of lead or aluminium/aluminium alloy, sometimes causes difficulties by improperly deforming during the molding process under forces applied by the molding die to material being molded into the non-metallic part. This results in a poorly molded part and the entire device usually must be discarded, adding to the cost of device manufacture.
In an effort to alleviate these difficulties it has been proposed that the non-metallic part be separately molded and then subsequently connected to the metallic part. Examples of connections include the use of adhesives and mechanical locking or clamping elements. However, the adhesives may break down or otherwise be unreliable over a period of time, leading to device leakage. The locking or clamping elements can in themselves be expensive as well as "fiddy" to apply. In addition, in an effort to provide the seal device with versatility, completion of the connection is often left to the end user of the device and that requires the user to initially cut a neat hole at a desired location in the metallic part, over which the non-metallic part is then positioned for connection. Cutting that hole can often be difficult to achieve correctly, with errors leading to wastage of metallic part material or potential leakage of the device during use.
A further seal device arrangement has involved separate molding of the non-metallic part and separate manufacture of a rigid base part on which the non-metallic part is then fitted. The base part has an upstanding boss whilst the non-metallic part has a skirt which overlies the boss for securing thereto. The skirt may be secured by means of a peripherally extending clamp element, or the boss and skirt may be provided with peripherally extending ribs and grooves which interlock one another to form a mechanical interconnection. However, that interconnection may be relatively easily broken or disturbed, again leading to potential leakage of the device in use. Moreover, to provide rigidity in the boss, the base part is usually molded of concrete, terracotta or rigid plastic material into a final shape, such as a roofing tile or shingle, so that its use is somewhat limited to the molded shape.